The present invention relates to a method and apparatus for detecting unknown objects such as dangerous weapons kept secret by persons, animals and the like. More specifically, this invention concerns a method and apparatus for visualizing unknown objects suitable for use in checking one's belongings at airports or the like.
As well known in the art of checking one's belongings at airports or the like, x-ray seeing-through check for one's baggages, and magnetic check and body check for human body are widely adopted.
Of the above prior art techniques, the magnetic check for a person has a fear of failing to find dangerous weapons or the like, depending on the locations where the person hides the weapons and on other conditions. The body check for finding dangerous weapons takes long time, and in addition it requires thoughtful care of personal rights.
According to the present invention, unknown weapons such as dangerous objects hidden by persons or animals are visualized using pulsating radio waves. A prior art relevant to this invention in this sense is a radar which transmits a pulsating radio wave to the broad area in the air and receives a reflected radio wave to detect a presence of a target substance. However, a conventional radar uses a broad radio wave beam so that it is impossible to visualize a target substance minutely. Also as seen from an airplane radar, it is not necessary to discriminate the target from other targets (e.g., ground or the like) so that conventional radar technique cannot be adopted for checking one's belongings.